Internet commentary

Internet commentary

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  In language, the ignorant have prescribed laws to the learned.(Richard Duppa, Maxims, 1830, No. 252)

In this prologue, I shall be slightly more technical than usual. I wish to discuss mark-up languages used for generating Internet pages on the World Wide Web. The basic language which has been used up to now is called HTML or hypertext mark- up language. All the WYSIWYG translators change what the designer sees on the screen into HTML. The more savvy website designers may write a whole page or part of it directly in HTML, using an Ascii editor. But what is HTML?

HTML is a subset of SGML or Standard Generalised Mark-up Language. This is a very complex mark-up language with very strict rules and is difficult to use. The subset was created to make a simple, easy-to-use, language specifically for Internet applications. It was originally intended, in version 1, to handle just text, without any possibility of making a Web page attractive to the eye or to include graphics. As the requirements increased, so did the complexity of HTML. Even this was not enough, so that it became necessary to add scripts, JavaScript being the most popular. These allowed simple programmes to be executed within a Web page. Unfortunately, the flexibility that these offered has allowed poor programmers to produce bloatware pages and increased all sorts of security issues.

The basic concept of HTML is to surround each item in a page by two tags. For example, the tags at the beginning and end of a paragraph are < p > and < /p> respectively. However, lazy programmers (although not strictly accurate, I shall use this term to describe authors who write in HTML) soon found that some end tags are not necessary in the majority of browsers and the latter were increasingly tolerant of such poor programming, as a result. In other words, your Microsoft Internet Explorer or Netscape Navigator allowed countless sins. The number of permitted tags in the later versions of HTML run into the hundreds, although most programmers may use only 20 or 30 on a regular basis.

Over the past couple of years, a new buzzword has appeared, XML or extensible mark-up language. The latest word processors all include means of writing in this language, even though very few persons are aware of what it is about or what it does. Even though it offers many advantages for Web page design, most programmers have found that it is far too difficult to understand and they simply do not have time to get down to the nitty gritty of it. The key advantage of XML over HTML, is that a programmer may create his own tags. As an example, if you wish to incorporate a database of fluxes in a web page, it may simplify your task by creating such tags as <flux_name>, </flux_name.> <flux type> and so on. A single entry on a page may then appear as follows:

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  <flux_database.><entry><flux_name.Smith's X123,/flux_name><flux_type.water-soluble,/flux_type><flux_activity.high,/flux_activity><flux_cleaner.water,/flux_cleaner></entry></flux_database>

I don't think that I shall need to elaborate to show, from this simple example, that it is very much more powerful than HTML, even if it is so much more difficult to use. So the question is, should webmasters make the effort to write their pages in XML? The simple answer is No. This is because the current browsers are not able to take advantage of all that XML offers. Probably, in my opinion, the situation will not improve over the next few years, until all browsers are XML-compliant. One can therefore legitimately ask oneself what all the fuss is about.

The answer is that there is a compromise available, called XHTML. This is beginning to come to life, since version 1.1 was published earlier this year. Programmers can easily make the transition from HTML to XHTML without busting their brain boxes. However, there are a number of things which must be remembered. Perhaps one of the most important is that the strict protocol is necessary – no more sloppily omitting end tags etc. Browsers can generally handle this easily, without modification. So what are the disadvantages?

Generally speaking, HTML documents begin with something like:

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  <<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML//EN"><html>

This is to tell the browser what it will be contending with, the minimum being the second line above. Because XHTML is really a modified XML, restricted essentially to HTML tags, its starting lines are somewhat different:

<?xml version="1.1" standalone="yes"?><!DOCTYPE html public "-//W3C//DTDXHTML 1.1 Transitional//EN" "http://www.w3.org/TR/xhtml1l/DTD/transitional.dtd"><html xmlns="http://www.w3.org/2001/ xhtml">

There are two important things which spring to the eye. The most obvious one is the references to the URL http://www.w3.org, which refers to the World Wide Web Consortium (W3C), in turn the authoritative body recommending the use of XHTML and writing its rules. The other one is the increased reference to DTDs and the specific transitional one. A DTD is a Document Type Definition and, as can be seen from the first example, is not new but has been largely ignored. In XHTML, it is mandatory to use one of three DTDs to validate the document. These are:

Strict: The W3C intends to phase out some of the weaker or superfluous HTML tags from XHTML as soon as would appear practical. A document type defined as Strict means that it will conform to future versions of XHTML and does not use any of the legacy tags likely to be eliminated.

Transitional: This defines the document as containing legacy HTML tags. Most early use of XHTML, where current HTML pages are translated to XHTML, will use this DTD, for safety.

Frameset: This is a slight departure from HTML. In HTML, a page which defines the size and contents of frames is defined uniquely as being between the tags ,frameset. and </frameset> instead of <body> and </body>, as in other pages. In XHTML, this is the same but, in addition, the whole document type must be defined accordingly. I suspect that this is because frames are also transitional (and a good thing, too: they have really outlived their usefulness).

I mentioned before that XHTML will not tolerate sloppy syntax or programming, such as the omission of end tags. There are some other rules that change slightly. In HTML, the tag for a horizontal line is ,hr. but it strictly should be <hr> </hr>, although the second element was invariably omitted because there was nothing to go between the two tags and it did nothing, in any case. In XHTML, this is called an “empty” tag, because it did not have any attribute or text. Empty tags are written in XHTML by, for example, </hr>, so that it is still permissible to use them without writing two whole tags. Tag names and their attributes and values must, in XHTML, be written exclusively in lowercase. It is no longer allowed to use, for example, <p align="CENTER">. This makes for a more consistent appearance and simplifies browser design. Also, all the attribute values must now be between inverted commas (quotation marks).

The above gives a very short introduction into the intricacies of XML and XHTML. Of course, I don't expect anybody to start using XHTML from what I have said. For further details, you can refer to the URL of the W3C website, referred to above. The object of this essay is to allow webmasters to decide whether to expand their knowledge at this stage or to wait until the maturity is such that it becomes more interesting. Just to give you a hint, my personal attitude will be to continue to use HTML for a limited time, while attempting not to use the tags which I have described as legacy in the Strict DTD, so that a transition to XHTML will be less painful when the time comes. It should perhaps be mentioned that most of the popular WYSIWYG HTML code generators have not yet made the transition. As for XML, I am not even going to bother to look at it, at least for the time being.

For the Review section of this Commentary, I shall revisit the lead-free debate. For those of you who subscribe to the IPC lead-free net list, you will realise that this subject is becoming more and more emotional rather than technical. I'll be using the same technique as I did last time, by just reviewing pages rather than websites. My Google search words are “lead free solder OR solders OR soldering”.

http://www.leadfree.org

Almost inevitably, the first reference to come up is the Home Page of the ITRI's (formerly known as the International Tin Research Institute) subsidiary site on lead-free soldering. The page itself is uninteresting but it has a menu leading to many other, much more useful, pages. The site is worth exploring but it is a bit of a sheep in wolf's clothing because, despite the.ORG domain, it is undoubtedly commercial, promoting the sale of tin.

http://www.solderworld.com/

If you don't believe that the last reference has commercial overtones, you must visit this site which is sponsored by the same organisation. Again, this opens into a Home Page which, through a menu, can lead you to lists of suppliers of products for lead-free soldering. Interestingly, in the case of products containing alloys, the indexing is done according to the alloy itself. Actually, I believe that this is a very useful directory.

http://www.elvesofester.com/leadfree.html

This is a very interesting reference, although it has nothing whatsoever to do with the electronics industry. It shows that the artisans making stained glass windows have exactly the same problems as we do in our industry. This page is very well worth reading if only because it shows that other sectors have come to similar conclusions as we have.

http://www.ivf.se/elektronik/Ep/Publications/LeadfreeSoSanAbstr.htm

This page offers an abstract of a paper (for sale) published by the famous Swedish organisation, IVF, describing the addition of a small quantity of zirconium to lead free alloys, in order to reduce the grain sizes. At the same time, it would seem that the hardness of the alloy also increases. Before the question arises, the incorporation of 0.2 per cent of zirconium will not significantly increase the price of the alloy in itself, but the method of incorporation (cold attrition milling) may do so. An interesting idea but too early to state whether it has any commercial value.

http://www.boulder.nist.gov/div853/ lead free/props01.html

The US National Institute of Standards and Technology and the Colorado School of Mines have combined to produce a very useful database. This collects together in one document nearly 50 tables of properties of lead free solders of many different alloys. For anybody wanting reliable data on an alloy, then this is the place to go to.

http://www.tms.org/pubs/journals/JOM/0106/Frear0106.html

This is a full article entitled “Pb-Free Solders for Flip-Chip Interconnects”, re-produced from the Journal of Manufacturing, complete with all the references and figures. It is long to download. Nothing further need be said because the title is self- explanatory.

http://www.alphametals.com/lead_free

Of course, the solder manufacturers also have their websites. This one, from Alpha Metals, appears to have quite a lot of information accessible from this page. Unfortunately, I could not investigate this in detail because the Alpha server was either functioning very poorly or had an inadequate connection to the Internet backbone, at the time of writing this article.

http://www.npl.co.uk/npl/cmmt/programmes/mpm/lfs.html

The UK National Physical Laboratory has been a leader in the move towards lead-free solders and has done valuable work towards this end. However, I find a very telling sentence on this page, “Legislation on the use of lead, along with commercial pressures, will force the industry to use lead-free solder within a few years.”. You will note that there is no mention of scientific proof that lead in solder is harmful to humans or to the environment. It is known that the European legislation is not based on a scientific risk assessment and has been pushed through on false premisses. Notwithstanding, useful information is obtainable here for the inevitable.

http://www.jgpp.com/projects/lead_free_soldering/lead_free_soldering.html

This page appears to be a description of a project to demonstrate and validate lead-free solders, run by an organisation, the Joint Group on Pollution Prevention. The page itself and its sister pages seem to be rather weak on what they are trying to achieve. However, they appear to hold regular meetings and this may be of interest to our American friends.

http://it.jeita.or.jp/jhistory/english/information/pbfree/roadmap2.html

It is well known than the Japanese have been pioneering the use of lead-free solder in some low- cost consumer goods. The motivation behind this has been purely commercial, in an attempt to show consumers that the companies “care” for the environment. It would appear, from the latest information that, although it was successful initially, the move has backfired on the manufacturers. This page, published by the Japan Electronic Industry Development Association, is a very good question and answer document, entitled “Challenges and Efforts towards Commercialisation of Lead-free Solder”.

http://www.btu.com/html/Solutions/ARTICLES/leadfree.htm

This would appear to be an article “reprinted” from Circuits Assembly, last year. It is entitled, “Optimising Solder Joint Quality - Lead-free”. It describes a designed experiment, using two alloys and three flux types. A statistical analysis of the results is given. Unfortunately, the reader cannot benefit directly from this as the flux types were not revealed but contact with the authors may possibly remedy this situation.

http://www.kester.com/leadfree/leadfree_update.htm

Obviously, Kester Solders have an interest in the lead-free debate. This page is somewhat unexpected from a solder manufacturer who may be expected to push towards the higher cost lead-free solders, impartially weighing up some of the pros and cons. The title of the page is, “A Concise Snapshot of the Lead-Free Soldering Issue Today”. What is good is that the company still considers there is an issue and not just a fait accompli, as many others have done. In fact, this is the first page of my review with sound references to papers presented by opponents to lead-free soldering on the grounds of the environment. Yes, there is good reason to believe that the environment will suffer from the introduction of lead-free soldering.

http://epims.gsfc.nasa.gov/ctre/act/techdocs/solder/leadfree.htm

This is another paper written by an expert from the Goddard Space Flight Center. It is best summarised by the last part of the abstract, “The purpose of this report is to provide background information on environmental concerns of lead-based solders, pros and cons of continuing to use tin/lead solders, properties and preliminary technical assessment data from potential alternative lead-free solder alloys.”. It is a lengthy document discussing various alloys, including some quite exotic ones.

http://www.ate.agilent.com/emt/industry/leadfreesolder/index.shtml

To remind you, Agilent is an offshoot company from Hewlett-Packard, incorporating that part of the company not involved with IT equipment. This page is interesting in that it discusses the X-ray inspectability of lead-free solder joints, which are obviously less opaque than those made with a tin- lead alloy. This is a matter which is often ignored but is very important to people using BGA and, above all, micro-BGA components. There is a full PDF paper downloadable from this page, as well as an abstract describing the problem.

http://www.wartonmetals.co.uk/lead_free_reports.htm

This page is a summary of much of the data available in the UK on the subject of lead-free soldering. It is edited by a manufacturer of such solder. There is nothing outstanding in the page, other than quotations from many sources. As such, it may be considered as useful, provided that one can support the flashing link to the commercial pages (I would advise those persons suffering from epilepsy and who are sensitive to flashing lights to avoid this page).

http://www.ti.com/sc/docs/products/leadfree

For our final word, let us enter into the world of components. Texas Instruments has been famous for supplying integrated circuit packages with a nickel/palladium finish on the solderable leads for many years. It has not been without problems, of course, but it is lead-free and should present no greater difficulties using these alloys than with lead-containing solder.

This would appear to be a fairly formidable range of valuable pages to visit. However this is only a paltry fraction of those that came up in the search engine (about 67,000 results). On the whole, it would appear that there is an enormous amount of technical information available on the Internet on the subject, of varying degrees of quality. The one thing that has become apparent in the hundred or so pages that I looked at to write this article and that is the paucity of scientific information on the hazards that lead in solder may present. This tends to confirm my opinion that the whole movement towards lead-free soldering in electronics is based on the dirty buzzword “lead”, rather than a reasoned and reasonable action. As I said at the beginning of this section, this is a highly emotional subject, as well as having severe negative impacts on the economy of the electronics industry and the reliability of its products. Additionally, it is probable that the environmental damage done as a result of introducing lead-free electronics is considerably greater than it would have been if the status quo had been allowed to continue - not to mention the pollution caused by all the hot air that comes out of the mouths of the proponents and opponents! In any case, the holistic answer to the problem is recycling the solder which is relatively easy and economical, once the infrastructure is in place (in Europe, it will have to be put in place within a few years, as well as going mandatorily lead-free, a paradox). This would allow lead to be continued in use without any of the pretended risk. This easy solution to the whole problem hardly came up, at all, in my search. Why?

Brian EllisCyprusb_ellis@protonique.com